Introduction to Liferay Development

How many times have you had to start over from scratch? Probably almost as many times as you’ve started a new project, because each time you have to write not only the code to build the project, but also the underlying code that supports the project. It’s never a good feeling to have to write the same kind of code over and over again. But each new project that you do after a while can feel like that: you’re writing a new set of database tables, a new API, a new set of CSS classes and HTML, a new set of JavaScript functions.

Wouldn’t it be great if there was a platform that provided a baseline set of features that gave you a head start on all that repetitive code? Something that lets you get right to the features of your app or site, rather than making you start over every time with the basic building blocks? There is such a thing, and it’s called Liferay Portal.

Liferay Portal offers you a complete platform for building web apps, mobile apps, and web services quickly, using features and frameworks designed for rapid development, good performance, and ease of use. The base platform is already there, and it’s built as a robust container for applications that you can put together in far less time than you would from scratch.

It also ships with a default set of common applications you can make use of right away: web experience management, collaboration applications such as forums and wikis, documents and media, blogs, and more. All of these applications are designed to be customized, as is the system itself. You can also extend them to include your own functionality, and this is no hack: because of Liferay’s extensible design, customization is by design.

Liferay Portal ships with suites of applications to get you started building your site quickly.

In short, Liferay was written by developers for developers, to help you get your work done faster and more easily, to take the drudgery out of web and mobile app development, so that writing code becomes enjoyable again.

One of the most often cited best characteristics of Liferay is how versatile it is. It can be used to build websites of all sorts, from very large websites with hundreds of thousands of articles, to smaller, highly dynamic and interactive sites. This includes public sites, internal sites like intranets, or mixed environments like collaboration platforms.

Developers often choose Liferay for one of these cases and quickly find that it is a great fit for completely different projects.

Liferay Portal is based on the Java platform and can be extended by adding new applications, customizing existing applications, modifying its behavior, or creating new themes. You can do this with any programming language the JVM supports, such as Java itself, Scala, jRuby, Jython, Groovy, and others. Liferay Portal is lightweight, can be deployed to a variety of Java EE containers and app servers, and it supports a variety of databases. Because of its ability to be customized, you can add support for more app servers or databases without modifying its source code: just develop and deploy a module with the features you need.

Speaking of code and deploying, here are some of the most common ways of expanding or customizing Liferay Portal’s features:

Developing a new full-blown web application. The most common way to develop web applications for Liferay Portal is with portlets, because they integrate well with other existing applications. You are not, however, limited to portlets if you don’t need to integrate your apps with others.

Customizing an existing web application or feature. Liferay Portal is designed to be extended. Many extension points can be leveraged to modify existing behavior, and most of these can be developed through a single Java class with some annotations (more details later).

Creating a new web service for an external system, a mobile app, an IoT device, or anything else.

Developing a mobile app that leverages Liferay as its back-end, which you can write in a fraction of the normal time thanks to Liferay Screens and Liferay Mobile SDK.

Developing a custom theme that adapts the look and feel of the platform to the visual needs of your project.

Developers use Liferay Portal in many ways.

The Liferay platform can be used as a headless platform to develop web or mobile apps with any technology of your choice (Angular, React, Backbone, Cocoa, Android’s Material Design components, Apache Cordova, etc). It can also be used as a web integration layer, leveraging technologies such as portlets to allow several applications to coexist on the same web page.